A non-volatile memory device, such as a flash memory used in a mobile phone, may stores different types of data therein. For example, a flash memory may be fabricated to store a first type of data that is not required a higher reliability, such as audio data, and a second type of data that is required a higher reliability, such as ID, program and phone numbers.
To realize such function of technology, a semiconductor chip including both a flash memory and a EEPROM may be used in an electric device. However, two different fabrication processes are required to make a single chip of memory device, including a flash memory and a EEPROM, so that the fabrication cost would be high.
According to another aspect, a flash memory and an EEPROM are molded in a single package so that non-important data are stored in the flash memory and important data are stored in the EEPROM. However, it is difficult to make a memory device having an optimum amount of storage capacity. Consequently, the memory device costs high.